Question

Table 1: invTypes with columns typeID,groupID,typeName,description
Table 2: item_value with columns typeID,volume,avg,max,min,stddev,percentile,updated_on

I need to return all of the above columns where the latest updated_on (datetime) field as the deciding factor. I would like to return the latest datetime for each day with all of the information from table 1 and table 2 as the result.

Answer 1

This is how you get the rows corresponding to the most recent updated_on for each date in your item_value table:

SELECT
  invTypes.*,
  item_value.*
FROM
  item_value
INNER JOIN
  (
    SELECT
      MAX(updated_on) AS `updated_on`
    FROM
      item_value
    GROUP BY
      DATE(updated_on)
  ) latest
ON
  latest.updated_on = item_value.updated_on
INNER JOIN
  invTypes
ON
  invTypes.typeID = item_value.typeID
ORDER BY
  item_value.updated_on